1864.] 673 



give the descriptions of the two new species, and also to notice the va- 

 riations in the species already described. 



A list of the remaining species of Hymenoptera, composing the very 

 interesting collection made by Mr. Ridings, will be given in a paper 

 now in course of preparation, in which the numerous new species will 

 be described. 



For the specimens used in the preparation of this paper, the Ento- 

 mological Society is indebted to the kind liberality of Dr. Thomas B. 

 Wilson. 



Genus MASARIS. Fabr. 

 Uasaris vespoides, Cresson. 



Masaris vespoides, Cresson, Proc. Ent. Soc. Phil. ii. p. 69; pi. 4. (1863.) 



The males vary little in their markings from the specimen first de- 

 scribed. The transverse line between the insertion of the antennae 

 varies somewhat in shape, and sometimes, instead of being dilated in 

 the middle as in the type, it is dilated at each end. The anterior mar- 

 gin of the prothorax varies in width, and is more or less indented on 

 each side posteriorly; the spot on the pleura, just beneath the anterior 

 wing, is sometimes wanting ; the spot on the tip of the scutellum is 

 sometimes much enlarged and somewhat cordate or lunate, and some- 

 times it is entirely obliterated ; the acute posterior angles of the meta- 

 thorax are sometimes entirely yellow, sometimes merely margined with 

 yellow. The bands on the abdomen above vary as follows : — that on 

 the second segment is sometimes continuous, with a deep, square emar- 

 ginatiou on each side anteriorly ; the bands on the remaining segment.s 

 are always continuous, those on the third and fourth segments are more 

 or less deeply and squarely indented on each side anteriorly; the bands 

 on the fifth and sixth segments are always very broad, that on the fifth 

 having a transverse black spot on each side, sometimes there is a deep 

 emargination on each side anteriorly, the band on the sixth segment 

 has sometimes a narrow black line on each side nearly confluent with 

 the posterior margin ; the last segment, in one specimen, is merely 

 upped with yellow, while in all the other specimens it is at least one- 

 half yellow, as in the type. 



The females vary considerably, especially in the markings of the ab- 

 domen, the bands being sometimes very broad, sometimes narrow, and 

 in two specimens resembling those of the % ; the band on the first seg- 

 ment is rarely continuous, mostly more or less interrupted on the disk 



